Pool Chemical Calculator

Free exact dosing — chlorine, pH, alkalinity, shock & CYA

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Units:

Balance your pool in the right order — saves money and time

Every certified pool technician knows chemistry only works in the correct sequence. CDC & PHTA recommend this order:

1. Alkalinity 80–120 ppm
2. pH 7.2–7.6
3. Calcium 200–400 ppm
4. CYA 30–50 ppm
5. Chlorine 1–3 ppm
⚡ Quick Fix Mode

What's wrong with your pool?

Select pool size and problem for instant dosing — no deep knowledge needed.

Step 1 — What are you treating?
Step 2 — My pool is approximately:
Step 3 — My problem is: (pick one or more)

⚗️ Sanitizer

⚖️ pH & Balance

💎 Calcium & Minerals

🌊 Water Appearance

🦠 Algae

📅 Situations

⚠️ Please select a pool size first.

Your dosing plan:

Starting-point estimates. Test after each addition. Use the Full Calculator below for exact dosing.

Full Calculator — enter your test results

Pool Volume Calculator

Enter dimensions to calculate exact volume. Auto-fills all calculators.

Same as shallow if flat-bottomed

Pool Volume
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✓ Volume saved — switch tabs to calculate doses

Chlorine Calculator

🧂 Salt pool: your salt cell generates chlorine continuously. Only add supplemental chlorine if FC drops below 1 ppm between cycles.
🛁 Spa/Hot Tub: Use dichlor granules only — liquid chlorine and trichlor tabs are not suitable for spas. CDC minimum: 3 ppm. Target 3–5 ppm. Hot water (100–104°F) breaks down chlorine 2–3× faster than a pool. Test before every use.

CDC recommends 1–3 ppm free chlorine. With CYA, maintain at least 2 ppm. Always balance pH first.

CDC pools: 1–3 ppm · hot tubs: 3–5 ppm

pH Calculator

🧂 Salt pools: pH naturally drifts UP as salt cells produce hydroxide ions. Test pH 2–3× per week. Muriatic acid is the most-used correction.

At pH 8.0, chlorine is only 21% as effective as pH 7.4. PHTA/CDC: 7.2–7.6. Adjust alkalinity before pH.

PHTA/CDC: 7.2–7.6

Total Alkalinity Calculator

Total alkalinity anchors your pH. NSPF recommends 80–120 ppm. Fix alkalinity first — pH often corrects itself.

NSPF ideal: 80–120 ppm

Pool Shock Calculator

🧂 Salt pool shock: use non-chlorine shock (MPS) to avoid over-stabilising CYA. Cal-Hypo is fine for occasional green-pool treatment.
🛁 Spa/Hot Tub: Use non-chlorine shock (MPS) after every use to oxidise contaminants. Shock weekly with dichlor for deeper sanitisation. CDC recommends daily-to-weekly shock depending on usage. Do not enter spa until FC returns to 3–5 ppm.

NSPF recommends at least 10 ppm. Green pools: 20–30 ppm. Shock at dusk. No swimming until FC < 4 ppm.

Standard: 10 ppm · Green pool: 20–30 ppm

CYA / Stabilizer Calculator

🧂 Salt pools: CYA target is 60–80 ppm (higher than chlorine pools). CYA protects the chlorine from UV. Only reducible by draining and refilling.
🛁 Spa/Hot Tub: CYA is not recommended for spas. Spas are refilled every 3–4 months so CYA accumulation is manageable by draining. For outdoor spas exposed to direct sunlight, a maximum of 30 ppm is acceptable. Dichlor adds ~9 ppm CYA per 10 ppm chlorine added — monitor carefully and drain when CYA exceeds 30 ppm.

CYA protects chlorine from UV — without it, sunlight destroys ~75% of chlorine within 2 hrs. CDC/PHTA: 30–50 ppm outdoors. Above 80 ppm, CYA impairs chlorine effectiveness.

Chlorine pools: 30–50 ppm

Salt Level Calculator

Most salt chlorine generators (SWGs) require 2700–3400 ppm. Check your generator manual for exact target. Always use pool-grade sodium chloride — not table salt or rock salt.

Most SWGs: 2700–3400 ppm. Check your manual.

Bromine Calculator

For spas and hot tubs. CDC recommends 4–8 ppm bromine. Add tablets to a floater or dispenser only — never directly to spa water.

CDC spas: 4–8 ppm

Ideal Pool Chemistry — CDC & PHTA Standards

Free Cl
1–3 ppm
pH
7.2–7.6
Alkalinity
80–120 ppm
CYA
30–50 ppm
Calcium
200–400 ppm
Salt
2700–3400 ppm

Sources: CDC Healthy Swimming, PHTA, NSPF Pool & Spa Operator Handbook

🧪 Pool Chemicals & Testing

Products used with this calculator — via Amazon & eBay

AquaChek 7-Way Test Strips — 100 ct
AquaChek 7-Way Test Strips — 100 ct
Quick daily testing for pH, free chlorine, bromine, alkalinity, hardness & CYA. #1 test strip brand used by pool pros.
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In The Swim 3" Chlorine Tablets — 50 lb
In The Swim 3" Chlorine Tablets — 50 lb
Slow-dissolving trichlor for daily sanitising. 90% available chlorine, UV-protected, individually wrapped.
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In The Swim Cal-Hypo Shock — 12×1 lb bags
In The Swim Cal-Hypo Shock — 12×1 lb bags
Pre-measured 1 lb bags. 68% calcium hypochlorite. Treats 10,000 gal per bag. Weekly shock or after heavy rain.
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In The Swim Alkalinity Increaser — 25 lb
In The Swim Alkalinity Increaser — 25 lb
100% sodium bicarbonate. Raises total alkalinity to stabilise pH. 1.5 lb per 10,000 gal raises TA by ~10 ppm.
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Pool pH Down — Lowers pH Safely
Pool pH Down — Lowers pH Safely
Granular sodium bisulfate — safer and easier than muriatic acid. Lowers pH quickly. Protects eyes and skin.
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Pool pH Up — Raises pH Fast
Pool pH Up — Raises pH Fast
Raises pH when water becomes too acidic. Fast-dissolving sodium carbonate granules. Prevents equipment corrosion.
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Clorox Pool Stabilizer & Conditioner — 4 lb
Clorox Pool Stabilizer & Conditioner — 4 lb
100% cyanuric acid. Protects chlorine from UV — without CYA, sunlight destroys 90% of chlorine within 2 hours.
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Pool Grade Sodium Chloride Salt — 40 lb
Pool Grade Sodium Chloride Salt — 40 lb
Pure pool-grade salt for saltwater systems. Never use table or rock salt. 40 lb treats ~1,200 gallons.
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🎉 Pool Fun & Accessories

Solar gadgets, lights & pool essentials — via Amazon & eBay

Solar Wireless Pool Thermometer
Solar Wireless Pool Thermometer
Solar-powered floating thermometer. Reads water temp from inside. Large backlit display, IP68 waterproof. Perfect for pools and hot tubs.
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Solar Floating Pool Lights — 2 Pack
Solar Floating Pool Lights — 2 Pack
RGB colour-changing floating lights. Solar powered, IP68 waterproof, remote control. Auto on at dusk. No batteries needed.
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Waterproof Bluetooth Pool Speaker
Waterproof Bluetooth Pool Speaker
Full-submersion waterproof Bluetooth speaker. Loud outdoor audio, long battery life. Perfect for pool parties.
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Solar Floating Pool Fountain
Solar Floating Pool Fountain
No wiring — drop it in. Solar-powered LED fountain with colour light show at night. Perfect for evening swims.
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Inflatable Pool Float Lounger
Inflatable Pool Float Lounger
Classic adult pool lounger. Durable PVC, comfortable design. Perfect for relaxing in the pool all summer long.
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Pool Leaf Skimmer Net — Fine Mesh
Pool Leaf Skimmer Net — Fine Mesh
Long-handle fine mesh skimmer for leaves, bugs and debris. Works with all pool types. Every pool owner needs one.
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Pool Chemical Calculator

Free exact dosing — chlorine, pH, alkalinity, shock & CYA

© 2026 poolchemcalc.app  ·  v20 · 23 May 2026

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